| 摘要 |
It consists in taking two metal strips which can be welded together and subjecting them to a flattening operation, passing them through a set of rollers which produce electric welding lines, with separation spaces equivalent to half the extent of the tubes to be obtained. The strips are passed through a press in order to flatten the weld lines. The ends of the zone of the future tube are opened and pressurized injection takes place via said ends (air or oil), which defines the tubular shape of the tubes which undergo calibration and then are subjected to the action of a rotary mandrel which produces the corrugations from the inside of the tubes. The shaped tube sections are separated from the whole by cutting. <IMAGE>
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